Where two ends of a cable such as a telecommunications cable are spliced together the splice area is ordinarily housed within a protective cover known as a splice closure. The design of these closures is dictated by the particular type of cable involved and its environment. For example, closures used with underground cable must ordinarily be watertight and closures for pressurized cables must be pressure tight. A common feature to most closures however is that they must provide some degree of cable strain relief to prevent cable strain from causing splice separation. For aerial cables such strain relief must be quite substantial.
With some closures strain relief is provide merely by the sealant used in sealing closed the end ports through which the cable enters the closure. For example, in U.S. Pat. No. 2,419,592 a moisture-proof cable connector has vinyl resin washers that incorporate a plasticizer sandwiched between two connector surfaces that are converged by rotation of a threaded nut. Upon such convergence the plasticizer is caused to be pressed out of the washers to form an adherent film on a cable which extends therethrough. This film is the only structural element that provides strain relief. U.S. Pat. No. 3,875,325 discloses a waterproof type cable closure having greater strain-relief capability comprised of two hinged shell halves and a tie bar mechanically coupled to a cable at opposed closure mouth ends. The two tie bar to cable connections are made with apparatuses that comprise an inner shoe curved for positioning under the cable sheath to which is attached a threaded stud. This stud extends through an outer plate which overlays the cable jacket and is secured to the tie bar with a nut. Once a splice has been made and the tie bar connected for stiffening purposes, the closure is filled with a filling compound such as petroleum jelly and the two half shells closed.
Strain relief devices of the type described in the last mentioned patent which include a member positioned under the sheath of the cable itself, have found wide usage. For example, the Western Electric Types 20, 21, 30 and 31 closures each use this general type of strain relief apparatus. More specifically, within mating shell halves having unitary end ports through which the cables enter and are sealed to the closure, strain relief is provided by bands that are placed under the cable sheath about the cable core which are squeezed into gripping engagement by the fastening of the shell halves. The bands have ears that engage stop surfaces of the shell upon axial cable movement.
Though cable closures of the type described do provide substantial strain relief they do so with devices that are relatively complex and tedious to install in the field. In forming a splice along a telecommunications line the cable is often oriented such that it enters the closure end ports at a skewed angle to the closure axis. This makes it difficult to align and mount the strain relief devices so that they are properly seated within the closure. If seated improperly, as at a skewed angle with respect to the closure axis, the closure covers may not be closeable or at least not closed properly. It therefore would be desirable to provide a cable closure with strain relief apparatus which could be mounted to a cable within a closure during a splicing operation with ease and expediency and even in those situations where the cable is momentarily biased so as to enter the closure off the closure axis. It is to this task which the present invention is primarily directed.